Webamator

YouTube iframe embeds often load many unnecessary resources, which slows down your page. YEP: Optimize YouTube Embeds is a lightweight WordPress plugin that replaces YouTube iframes with a clickable preview image. 
The actual video loads only when the user clicks the play button, improving page load times and reducing initial page size.
<h3>External services</h3>
This plugin uses the external YouTube thumbnail service (https://i.ytimg.com) to display preview images of YouTube videos. 
When a page with a YouTube embed is loaded, the plugin requests the thumbnail image directly from YouTube servers. 
No personal data is sent from your site to YouTube, only the video ID (already public in the YouTube URL).
Privacy Policy: https://policies.google.com/privacy 
Terms of Service: https://www.youtube.com/t/terms

YEP: Optimize YouTube Embeds

Short Description: Load YouTube videos faster by replacing iframes with a preview image; the video plays only when clicked play.

This version of Easy Video Publisher is no longer under active development. Please use <a href="https://videopublisher.org/" rel="nofollow ugc">Easy Video Publisher Pro</a>.
Easy Video Publisher lets you quickly publish YouTube videos, use to Import YouTube videos from one or multiple YouTube channels.
Automatically set featured image and embed the video, use a custom title, or use the original YouTube video title.
Features:
<ul>
<li>Create posts from YouTube channel</li>
<li>Manually run Import to create new posts</li>
<li>Schedule posts or publish immediately.</li>
<li>Set custom post type</li>
<li>Set post status to publish, draft</li>
<li>Set post author</li>
<li>Use Multiple API Keys</li>
<li>Use YouTube Tags As WordPress Tags</li>
<li>Automatically Import and Set Featured Image</li>
<li>Exclude Video If It Already Exists</li>
<li>Set YouTube author as post author</li>
</ul>

Easy Video Publisher

Easy Video Publisher quickly publish YouTube videos, use to Import YouTube videos from one or multiple YouTube channels.

YEP: Optimize YouTube Embeds vs Easy Video Publisher